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post #1 of 6 (permalink) Old 06-25-2016, 12:09 AM Thread Starter
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Installing Alpine Head Unit in Alfetta

I'm replacing the Pioneer Radio/Casette deck that came with my Alfetta with a modern single-din head unit from Alpine, the CDE-HD148BT. This is my first time trying to install a car stereo, so I have no clue what I'm doing.

I was able to remove the Pioneer, and I'm now trying to make sense of all the wires. Aside from the speaker wires, there are two additional wires: an orange and a red wire. The red wire has an in-line spring-loaded 2A fuse, and the orange has an in-line spring-loaded 0.5A fuse. Both red and orange have constant power and are not tied to the ignition (that was also how the Pioneer worked... it would run even with car off). I traced the wires back as far as I could, and they're actually spliced together. Looks like the orange wire is spliced into the red wire.

Now for the questions...

1. Why are the orange and red wires together?? Is that bad? And why are they using two different types of fuses?

2. Should I connect my new Alpine to the orange and red wires? I could connect the battery lead and the switched power lead?

3. Do I need in-line spring-loaded fuses? I noticed there's a 10A fuse holder in the back of the Alpine Head Unit... does that mean I don't need other fuses?

4. If I do need in-line spring-loaded fuses, what amperage? 10A? 15A? Seems like the existing 2A and 0.5A fuses are not going to work.

5. Seeing as I don't know where this red and orange wire are coming from, would it be better to start with a new clean wire from the fuse box or from the battery?? I'm concerned about overloading that wire.

Any help would be appreciated.

Some photos of the wires....




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post #2 of 6 (permalink) Old 07-18-2016, 11:06 AM
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welcome! So... first, do yourself a favor and run fresh speaker wires from the Alpine harness to your speakers.

1. Why are the orange and red wires together?? Is that bad? And why are they using two different types of fuses?
A: no idea. They're both hot? Your radio will need a switched and unswitched 12v+. Switched is when you turn on the key, it turns on the radio. Unswitched keeps your radio's memory going while the car is off, very little draw there so now worries if your battery is healthy. Need to determine if these two are live when the key is turned on or if they're always hot. IMO what the previous owner did was put BOTH switched and unswitched from the harness to the on the unswitched 12v+ on the car so that you can listen to the radio with the car off. No problems with this as long as your battery and charging system is healthy and you don't overdo it. Other than that, make sure you have an excellent ground wire, as short as possible, that makes great contact with the body.

2. Should I connect my new Alpine to the orange and red wires? I could connect the battery lead and the switched power lead?
A: the manual should tell you which lead from the radio's harness goes to switched or unswitched. Connect accordingly.

3. Do I need in-line spring-loaded fuses? I noticed there's a 10A fuse holder in the back of the Alpine Head Unit... does that mean I don't need other fuses?
A: No, your leads come from the fuse box and there's one in the back of the head unit, so you're covered.

4. If I do need in-line spring-loaded fuses, what amperage? 10A? 15A? Seems like the existing 2A and 0.5A fuses are not going to work.
A: where are you seeing those 2A and .5A fuses? Whatever fuse is in the fusebox of your car that protected your other radio will be fine. My guess is it will be at least 5A and probably 7.5 or 10.

5. Seeing as I don't know where this red and orange wire are coming from, would it be better to start with a new clean wire from the fuse box or from the battery?? I'm concerned about overloading that wire.
A: Trace them back to your fusebox by pulling the fusebox and looking in back. Your car's owner's manual should tell you which fuse covers your radio - check and see what color is there behind that fuse. Otherwise, if your previous radio was connected to them, you'll be fine.

Good luck and post again if you need help.

Don

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post #3 of 6 (permalink) Old 07-18-2016, 12:51 PM Thread Starter
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Hi Don,

Thanks a lot for the reply. I tried a few different things since my first post, but I'm still at it... slowly figuring it all out.

I tried running power from the battery straight to the head unit using a 10 gauge wire with an in-line 10A fuse. I spliced the head unit's power and memory leads together and connected them to that 10A fuse protected line.

Everything worked perfectly for a couple of days, but the head unit eventually wound up draining my battery (and it's a relatively new battery), even though I made sure the head unit was powered off when the car wasn't running.

This surprised me a bit because that is essentially how my old radio was connected, and that old radio never drained the battery. I guess these newer head units work differently?

In any event, I've obviously abandoned that approach and am now going to keep the memory and power leads separate. I took a closer look at my fuse box and identified the switched and unswitched fuses. This brings me to your answer to my first question:

Quote:
1. Why are the orange and red wires together?? Is that bad? And why are they using two different types of fuses?
A: no idea. They're both hot? Your radio will need a switched and unswitched 12v+. Switched is when you turn on the key, it turns on the radio. Unswitched keeps your radio's memory going while the car is off, very little draw there so now worries if your battery is healthy. Need to determine if these two are live when the key is turned on or if they're always hot. IMO what the previous owner did was put BOTH switched and unswitched from the harness to the on the unswitched 12v+ on the car so that you can listen to the radio with the car off. No problems with this as long as your battery and charging system is healthy and you don't overdo it. Other than that, make sure you have an excellent ground wire, as short as possible, that makes great contact with the body.
Both of the wires that were connected to the old radio have constant unswitched power. Did a little investigating, and it looks like those wires (which are spliced together) are tied to fuse #5, which is an 8A fuse. I agree with you... I think the previous owner wanted to be able to listen to the radio with the car turned off. I used that radio for years without any battery drainage issues, but it appears that that approach will not work with this newer Alpine unit.

So, STEP #1 CONNECTING THE MEMORY LEAD: I'm going to remove the old splice, and connect that constant unswitched power (coming off fuse #5) to the Alpine's memory lead. That should work, right? My only concern is that fuse #5 is an 8A fuse, and the Alpine might need 10A (judging from the 10A fuse on the unit), but maybe for memory 8A is enough?

STEP #2 CONNECTING THE POWER LEAD: Fuses #6, #7, #8 are all 8A fuses and have switched power (tied to the ignition). I believe I need up to 10A to power the head unit. I therefore located the wire going INTO fuse #6, and spliced a separate wire to it, bypassing the 8A fuse. I plan on installing an in-line 10A fuse on that spliced wire and connecting that 10A fused wire to the power lead on the head unit.

This brings me to this...

Quote:
3. Do I need in-line spring-loaded fuses? I noticed there's a 10A fuse holder in the back of the Alpine Head Unit... does that mean I don't need other fuses?
A: No, your leads come from the fuse box and there's one in the back of the head unit, so you're covered.
Just wanted to clarify, so I don't actually need in-line fuses?

Thanks for the help!

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post #4 of 6 (permalink) Old 07-19-2016, 04:28 AM
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Quote:
Originally Posted by UomoTigre View Post
Hi Don,

Thanks a lot for the reply. I tried a few different things since my first post, but I'm still at it... slowly figuring it all out.

I tried running power from the battery straight to the head unit using a 10 gauge wire with an in-line 10A fuse. I spliced the head unit's power and memory leads together and connected them to that 10A fuse protected line.

Everything worked perfectly for a couple of days, but the head unit eventually wound up draining my battery (and it's a relatively new battery), even though I made sure the head unit was powered off when the car wasn't running.

This surprised me a bit because that is essentially how my old radio was connected, and that old radio never drained the battery. I guess these newer head units work differently?
In any event, I've obviously abandoned that approach and am now going to keep the memory and power leads separate. I took a closer look at my fuse box and identified the switched and unswitched fuses. This brings me to your answer to my first question:

Both of the wires that were connected to the old radio have constant unswitched power. Did a little investigating, and it looks like those wires (which are spliced together) are tied to fuse #5, which is an 8A fuse. I agree with you... I think the previous owner wanted to be able to listen to the radio with the car turned off. I used that radio for years without any battery drainage issues, but it appears that that approach will not work with this newer Alpine unit.

So, STEP #1 CONNECTING THE MEMORY LEAD: I'm going to remove the old splice, and connect that constant unswitched power (coming off fuse #5) to the Alpine's memory lead. That should work, right? My only concern is that fuse #5 is an 8A fuse, and the Alpine might need 10A (judging from the 10A fuse on the unit), but maybe for memory 8A is enough?[/QUOTE]

So, I think you're right: new head unit has too much draw from the unswitched 12v to connect that together with the switched 12v as the previous owner had done. Suggest you separate them and wire per the Alpine's instructions and you shouldn't have any problem - you just won't be able to listen to the radio unless the car is running or the key is turned to the accessories position. Not a big deal, and you'll save your battery! 8A is plenty for power backup on fuse 5, don't worry about that. It won't be drawing that much current while it's off.



Quote:
STEP #2 CONNECTING THE POWER LEAD: Fuses #6, #7, #8 are all 8A fuses and have switched power (tied to the ignition). I believe I need up to 10A to power the head unit. I therefore located the wire going INTO fuse #6, and spliced a separate wire to it, bypassing the 8A fuse. I plan on installing an in-line 10A fuse on that spliced wire and connecting that 10A fused wire to the power lead on the head unit.

This brings me to this...

Just wanted to clarify, so I don't actually need in-line fuses?

Thanks for the help!
No, I think another in-line fuse is redundant, but it won't hurt, either. Your head unit will be protected at the fuse box by the #6 fuse, and there's a fuse in the back of the head unit. You'll be fine.

I think you're all set. Don't forget a nice fat ground wire, as short as possible, with solid contact to the body. Don't be tempted to connect the black ground to another floating ground wire from the car's radio harness, run the head unit ground straight to the car's body via an existing bold or screw, and keep it as short as possible, i.e., don't run it up to the engine or back to the battery or anything, keep it as close to the head unit as you can. Most interference is introduced via a long ground wire.

Good luck!

Don Davis
Woodbridge, VA
1986 Spider
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post #5 of 6 (permalink) Old 07-19-2016, 09:17 AM Thread Starter
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Thanks, Don. I'll be back at it again this coming weekend. Hope to get it all working!

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post #6 of 6 (permalink) Old 07-19-2016, 09:43 AM
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Easy-peasy!

Quote:
Originally Posted by UomoTigre View Post
Thanks, Don. I'll be back at it again this coming weekend. Hope to get it all working!

Don Davis
Woodbridge, VA
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